"The manner in which the people were hustled into voting and the flagrant abuse of election procedures degraded the very concept of democratic choice," his statement said.

Some polling stations were busy, others deserted

Mr Khattak said observers who were supposed to be neutral had been seen "stamping ballots themselves".

"Voluntary turnout was very low," he said, with public sector workers being obliged to vote.

Many journalists have reported similar irregularities.

But the government insists the poll has been clean.

At Pakistan's last general election in 1997, official turnout was estimated to be 37% - a figure which opposition groups said was inflated.

Voters could cast their ballot anywhere provided they could show an identity card, driving licence or official letter, and electoral lists were abolished.

President 'indispensable'

General Musharraf seized power in a coup in 1999.

He has called parliamentary elections for October as part of his roadmap for the restoration of democracy.

Under the constitution,
the president should be chosen by the members of the national and provincial assemblies and the senate.

I voted eight times as it was not very difficult... It was really fun

Voter Nawaz Bhutto

However, the supreme court rejected an opposition attempt to halt the referendum, upholding General Musharraf's argument that the constitution also justifies referendums on matters of national importance.

He has argued that it is vital for him to stay in power in order to fulfil his vision of turning Pakistan into a modern, democratic, Islamic state.

The military, a key component of Pakistan politics, has been fully supportive of the holding of the referendum.